filestack/filestack-swift

//
//  CollageTransform.swift
//  FilestackSDK
//
//  Created by Mihály Papp on 15/06/2018.
//  Copyright © 2018 Filestack. All rights reserved.
//

import Foundation
import UIKit

/// The collage task accepts an array of Filestack file handles, storage aliases, or external URLs.
/// These files are appended in given order to the base file of the transformation URL.
/// Altogther the base image and the passed files are the images that will comprise the collage.
/// The order in which they are added dictates how the images will be arranged.
public class CollageTransform: Transform {
    // MARK: - Lifecycle

    /// Initializes a `CollageTransform` object.
    ///
    /// - Parameter size: Valid range: `1...10000` x `1...10000`
    /// - Parameter collection: CollageTransformCollection with added handles or direct links to images.
    init(size: CGSize, collection: CollageTransformCollection) {
        super.init(name: "collage")
        appending(key: "width", value: Int(size.width))
        appending(key: "height", value: Int(size.height))
        appending(key: "files", value: collection.files)
    }
}

// MARK: - Public Functions

public extension CollageTransform {
    /// Adds the `margin` option.
    ///
    /// - Parameter value: Valid range: `1...100`
    @discardableResult
    func margin(_ value: Int) -> Self {
        return appending(key: "margin", value: value)
    }

    /// Adds the `color` option.
    ///
    /// - Parameter value: Sets the background color to display behind the images.
    @discardableResult
    func color(_ value: UIColor) -> Self {
        return appending(key: "color", value: value.hexString)
    }

    /// Changes the `fit` option to every image from `auto` to `crop`.
    @discardableResult
    func cropFit() -> Self {
        return appending(key: "fit", value: TransformFit.crop)
    }

    /// Adds the `autorotate` option.
    @discardableResult
    func autorotate() -> Self {
        return appending(key: "autorotate", value: true)
    }
}

// MARK: -

/// Class that is used for creating and sanitizing collection of file handles, storage aliases, or external urls.
///
/// See also `CollageTransform`.
@objc(FSCollageTransformCollection)
public class CollageTransformCollection: NSObject {
    // MARK: - Internal Properties

    var files = [String]()
}

// MARK: - Public Functions

public extension CollageTransformCollection {
    /// Adding one resource to collection.
    ///
    /// - Parameter resource: File handle, storage aliase, or external url passed as String.
    /// - Returns: self
    @discardableResult
    @objc(addResource:) func add(_ resource: String) -> Self {
        return add([resource])
    }

    /// Adding few resources to collection.
    ///
    /// - Parameter resources: Array of file handles, storage aliase, or external url passed as String.
    /// - Returns: self
    @discardableResult
    @objc(addResources:) func add(_ resources: [String]) -> Self {
        files.append(contentsOf: resources.map { envelop($0) })
        return self
    }
}

// MARK: - Private Functions

private extension CollageTransformCollection {
    func envelop(_ string: String) -> String {
        return "\"\(string)\""
    }
}